Abstract
Prant heterotrimeric G proteins have been proposed to be involved in the transduction of several extracellular signals such as plant hormones, elicitor and light. In the plant G proteins, the precise intracellular localization of the subunits have not yet been analyzed. In the present work, we analyzed the localization of the subunits of the rice G protein.
1. Western blot analysis showed that the α, β, γ1, and γ2 subunits were localized in rice plasma membrane fractions.
2. Membrane-proteins solubilized with cholate were fractionated by gel filtration (Superdex 200 PC3.2/30, SMART System, Pharmacia). Two fractions of the G protein were obtained; one seemed to be a heterotrimer(s) (αβγ1 and/or αβγ2), and the other, a βγ dimmer(s) (βγ1 and/or βγ2). We propose that, in rice plants, a large amount of βγ dimmer is present in the plasma membrane in a form without the α subunit.
